Syracuse, NY -- Covanta Energy Corp., the company that runs the trash-burning power plant in Onondaga County, is trying to convince state officials for the third time in less than a decade that electricity made from incinerating garbage is renewable energy worthy of state subsidies.

The state Public Service Commission is expected to rule Thursday on Covanta’s petition to include “energy from waste” as a renewable power, on par with wind, solar and biomass. If the commission sides with Covanta this time — it rejected two previous requests — the company and other developers could apply for millions of dollars in state subsidies to build new trash-burning power plants.

The PSC’s decision is unlikely to have an impact on the Jamesville incinerator at Rock Cut Road, which Covanta operates for the Onondaga County Resource Recovery Agency. The only way the Jamesville plant could qualify for renewable-energy subsidies is if OCRRA and Covanta expand the facility, something both say they have no plans to do.

The main issue is whether Covanta and other developers build new plants in New York, which already has 10. Renewable energy subsidies would make it easier for Covanta to compete for municipal waste with landfills, which typically charge lower tipping fees to trash haulers, said James Regan, speaking for Covanta.

New York state collects about $200 million a year from utility customers on a monthly bill surcharge, which it uses to subsidize renewable power generators.

Covanta spent roughly $250,000 lobbying state and local officials between July 2010 and June 2011, according to state records. The company also has donated roughly $50,000 to political candidates and committees since January 2009, records show.

State Sen. David Valesky, a former member of the Senate energy committee, received $750 from Covanta in 2009 and $500 in 2010. Valesky could not be reached for comment.

Central New Yorkers have weighed in on both sides of the debate over Covanta’s request. Valesky and state Sen. John DeFrancisco both sent letters supporting Covanta’s position, as did Assemblyman William Magnarelli. Assemblyman Sam Roberts opposed Covanta, along with Syracuse Councilor-at-Large Jean Kessner.

OCRRA, which holds title to the Jamesville plant and leases it to Covanta, supports the company petition. Local environmental groups, Atlantic States Legal Foundation and the Iroquois Chapter of the Sierra Club, oppose it.

In 2004, when New York officials formed a plan to derive 25 percent of the state’s power from renewable sources — later boosted to 30 percent — they excluded municipal waste incinerators from the mix because of concerns over emissions of mercury and other air pollutants. Five years later, Covanta asked the PSC to reconsider, without success. Last February, the company filed the request that is pending.

Covanta argues that waste incineration is better for the environment than transporting garbage to landfills. And the company says burning trash to make electricity is cleaner and more efficient than burning landfill methane to make power — a technology that has been blessed by state regulators as “renewable” and made eligible for state subsidies. “You need to consider the fact that we keep waste out of a landfill in addition to generating electricity,” said Mike Van Brunt, Covanta’s director of sustainability.

But environmental groups complain that waste-to-energy plants foul the air. “Covanta is trying to pull the wool over our eyes by claiming trash-burning is clean,” said Laura Haight, of New York Public Interest Research Group. “It would be a misuse of public funds to put garbage incinerators on equal footing with wind and solar power for clean energy funds.”

In rejecting waste-to-energy as a renewable fuel in 2004, the Public Service Commission noted that for each megawatt of electricity produced, trash incineration caused six times as much mercury pollution as burning coal in power plants.

A more recent study by the state Department of Environmental Conservation showed the numbers were even worse. In 2009, five plants operated by Covanta in New York, including the OCRRA plant, spewed an average of 14 times as much mercury as the average coal plant, DEC officials said. The OCRRA facility, considered alone, emitted about 1.6 times as much mercury as the average coal plant.

DEC officials said burning trash is better for the environmental than sending it to landfills. But they advised the Public Service Commission not to allow trash incinerators to divert resources from zero-emission power sources such as wind and solar.

If waste-to-energy plants gain admission to the renewable club, they should be considered second-class citizens ranked below clean sources like wind and solar, DEC officials said.